Road Disc Brakes- Rotor Choice

[FactoryMatt]

mass is mass. slow to heat, slow to cool. shimano took a different route to maximize the heatsink-to-weight ratio. not the best for all applications, but pretty clever for most. magura uses 2.0 rotors for a reason. hope V4 uses 2.3mm rotors for a reason.

i use shimano on some bikes and Braking (sold by Miche) or Swisstop on others.

[MichaelB]

Lots of "thinking" going on in that video, and quite a few innaccuracies.

Yes the rotors are pinned to the spider, but that doesn't make them 'floating' rotors.

Some reasonable points raised, but really only opinion. Saying they last only 6 months without further details doesn't mean anything. Agree that the XTR rotors seem to rub after heavy braking more than the older RT86 icetech ones, but that's about it.

[pdlpsher1]

I don't have a weight or heavy braking issue so I replaced my front Ultegra 160mm on my gravel bike with XTR 160mm. It went from 122g. to 104g., saving 18g. I'm waiting for the 140mm XTR to be in stock to switch out the rear. My bike can only accept 160mm or 180mm on the front. The rear can accept either a 140mm or 160mm.

I know a bit about mass and heat transfer. The disk rotor on my tandem is 254mm. They are made by Shimano with Icetech technology. Despite the rotor size and Icetech, they have failed on me on a technical descent at high altitude where there's less air resistance.

[Ritsuke]

Since a lot of people have 140mm rotors at the back, can you just replace a 160mm with a 140mm rotor with no further adjustments? (Dura Ace groupset)
Can I keep the current (500km old) rotor as a replacement for the front one?

[tjvirden]

I don't have a weight or heavy braking issue so I replaced my front Ultegra 160mm on my gravel bike with XTR 160mm. It went from 122g. to 104g., saving 18g. I'm waiting for the 140mm XTR to be in stock to switch out the rear. My bike can only accept 160mm or 180mm on the front. The rear can accept either a 140mm or 160mm.

I know a bit about mass and heat transfer. The disk rotor on my tandem is 254mm. They are made by Shimano with Icetech technology. Despite the rotor size and Icetech, they have failed on me on a technical descent at high altitude where there's less air resistance.

Can you be a little more specific please? Was it simply 'fade', even with no air in the hydraulics? I'm guessing the disc on the rear and a different brake on the front?
I'm not surprised to hear of a problem - even with large disc diameter, the ratio of system weight to disc weight is high on a single, let alone a tandem. As you know, tandems push brake systems to their limit.

[tjvirden]

Since a lot of people have 140mm rotors at the back, can you just replace a 160mm with a 140mm rotor with no further adjustments? (Dura Ace groupset)
Can I keep the current (500km old) rotor as a replacement for the front one?

From 160 -> 140 you have to move the caliper (normally by taking off the adapter plate). The 500Km rotor should be ideal for the front.

[Ritsuke]

Thanks @tjvirden!

[jeho]

Anyone in here have a shop that has Galfer 160/140s in stock? TIA

[Kayrehn]

Anyone in here have a shop that has Galfer 160/140s in stock? TIA

Saw that on ebay, sold by a shop in Spain iirc, you can check it out there.

Sent from my SM-G930F using Tapatalk

[rides4beer]

By wearing rotors in 6 months,
I think his choice of brake pads and weather/cleaning procedure has something to do with it.

I'd be curious to see what pads he's using. I rode over 20,000km with ~230,000m of climbing last year and didn't wear out a set of XTR rotors, using resin pads. I weigh 84kg and like to descend fast, so that means hard braking (which is why I love disc brakes lol).

[FactoryMatt]

wow.

[pdlpsher1]

I don't have a weight or heavy braking issue so I replaced my front Ultegra 160mm on my gravel bike with XTR 160mm. It went from 122g. to 104g., saving 18g. I'm waiting for the 140mm XTR to be in stock to switch out the rear. My bike can only accept 160mm or 180mm on the front. The rear can accept either a 140mm or 160mm.

I know a bit about mass and heat transfer. The disk rotor on my tandem is 254mm. They are made by Shimano with Icetech technology. Despite the rotor size and Icetech, they have failed on me on a technical descent at high altitude where there's less air resistance.

Can you be a little more specific please? Was it simply 'fade', even with no air in the hydraulics? I'm guessing the disc on the rear and a different brake on the front?
I'm not surprised to hear of a problem - even with large disc diameter, the ratio of system weight to disc weight is high on a single, let alone a tandem. As you know, tandems push brake systems to their limit.

The pad material vaporized and resulted in a complete loss of braking. The vapor prevents the pad from touching the rotor, much like a puck on an air hockey table. Yes, the tandem has a caliper front brake and a rear disk brake. On the tandem the rear wheel provides majority of the braking force, unlike on a single bike. Some older model tandems use a drum brake with a large amount of material to act as a large heatsink. They are designed as a drag brake with a control lever mounted on a bar end. They are meant to be turned 'on' and left on for the entire descent.

[Tifosiphil]

What is everyone using as their pad of choice currently? I've been running the Dura Ace stock pads for the last 4 months but looks like these will have worn out after around 1500miles.

Been plenty happy with these but is there another aftermarket option I am overlooking?

[TobinHatesYou]

The pad material vaporized and resulted in a complete loss of braking. The vapor prevents the pad from touching the rotor, much like a puck on an air hockey table. Yes, the tandem has a caliper front brake and a rear disk brake. On the tandem the rear wheel provides majority of the braking force, unlike on a single bike. Some older model tandems use a drum brake with a large amount of material to act as a large heatsink. They are designed as a drag brake with a control lever mounted on a bar end. They are meant to be turned 'on' and left on for the entire descent.

Mechanical or hydro disc? The extra hose length leads to slop in the brake feel / lever actuation over time.

I can assure you that you did not create some kind of gas boundary layer that could overcome the force of the pistons sandwiching the rotor. It sounds like you simply glazed the pads or experienced severe fade with a brake system that needed to be bled or flushed.

[snaxez]

So difference with XT and XTR Freeza rotors is only the cooling fins color and price? (RT-MT800 vs RT-MT900)